Screw air compressor abnormal sound fault solution summary

Screw compressor is a kind of power equipment widely used in the field of petrochemical and industrial production, and its safe and reliable operation is of great significance to ensure production, so it is necessary to focus on it.

Screw compressor host cylinder parallel with a pair of intermeshing spiral male and female rotor, between the rotor and between the casing and the rotor to leave a very small gap, theoretically no metal contact in operation. Therefore, from the structural principle, the screw compressor has the characteristics of stable operation and low noise compared with the traditional piston compressor.

However, many screw compressor users will encounter abnormal noise when using the equipment, such as metal collision sound, uniform knocking sound, friction whistling sound and so on. Due to the different causes of the fault, the external manifestations of the abnormal sound and the location of the occurrence are also different. This paper makes a brief analysis of the different causes of abnormal sound of the compressor and provides corresponding solutions for the reference of the compressor peers only.

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1. Reasons for abnormal noise

: The belt is too loose, and the matching degree of the active and passive belt grooves is too large, causing slippage and squealing (belt drive type). Compressor belt slippage can be judged and determined from the following aspects:(1) When you are close to the equipment, you can smell a burnt smell of the belt. If you observe carefully, there will be belt debris on the ground near the belt;(2) There is a kind of between the pulley and the belt Abnormal friction sound;(3) Due to uneven load, the current swings.

Solution: Rotate the adjusting bolt, adjust the belt to the appropriate tightness, the deformation is less than 5mm, but not too tight. After readjustment, operate with load. If it still slips, replace the belt.

The replacement of the belt is basically the same as the adjustment procedure of the belt, but it should be noted that when replacing the belt, you cannot replace only one belt, otherwise the new belt will be damaged due to the different belt tension. At the same time, be careful not to splash the lubricating oil. On the belt or pulley to prevent the belt from slipping.

2. Reasons for abnormal noise

: The screw compressor is short of oil during operation, so that the yin and yang screws are directly engaged without lubricating oil lubrication, and the dry friction of metal produces whistling sound.

The oil-injected screw compressor has no synchronous gear structure, and the male rotor directly drives the female rotor to rotate, but there is no direct contact between the two. The lubricating oil injected into the head establishes an oil film to isolate it. Therefore, for the screw compressor, the role of lubricating oil is very important. If the screw compressor "lack of oil" phenomenon, will lead to direct contact with the screw rotor, abnormal noise, resulting in bearing damage and other failures.

However, the "lack of oil" in the nose is not necessarily the total amount of lubricating oil is insufficient, there may be other reasons for local oil shortage and low lubricating oil pressure. Direct causes include: oil failure, oil cooler, blockage of oil pipeline, loose oil pipe joint and oil leakage; Indirect faults may include: minimum pressure valve failure, use of unqualified compressor lubricating oil, nonstandard design of oil and gas separation tank, damage to oil return check valve, improper installation of oil return pipe, large gas consumption, overload and low pressure use (or tight matching of oil treatment capacity selected before the machine leaves the factory with machine displacement), etc.

Solution: check the oil level, replace the oil filter, deal with the fault site and adjust the system configuration. When filling lubricating oil to the compressor host, at least let the oil soak to 3/4 of the rotor. It should be noted that in actual operation, some people only know that the operation of the equipment will cause the screw compressor to lack oil due to untimely addition. In fact, for those long-term shutdown without screw compressor, the oil inside the head is often insufficient. At this time, if you rashly boot, it is easy to cause an instant lack of oil. Therefore, the long-term shutdown of the screw compressor to the head of the first to add a sufficient amount of oil, and then boot.

3. Abnormal noise reason

: The intake valve is not closed tightly, the air leakage is large, and the intake valve backstop vibrates. The noise generated by the vibration of the check valve mainly comes from the lift-type check valve. Generally, the check valve is installed at the outlet of the compressor to prevent the high-pressure gas from returning to the system when the compressor is stopped.

Solution: replace or adjust the fault valve. The following points should be paid attention to when assembling the parts of the valve after inspection and repair:(1) the parts of the intake valve of the screw compressor should be clean;(2) The contact between the valve plate and the valve seat, the radial clearance between the valve plate and the lift limiter, the take-off amount of the valve plate, and the specifications of the spring meet the design requirements;(3) When replacing internal parts (such as valve plate, buffer plate, spring, etc.), all must be replaced at the same time;(4) Leakage test: Leakage test is required before installation of air valve.

4. Reasons for abnormal noise

: Motor bearing failure

solution:(1) When the motor is running, a screwdriver can be used, the tip is against the outer cover of the bearing, and the ear is close to the screwdriver's wooden handle to monitor the sound of the bearing. If the rolling body has a faint rolling sound in the inner and outer rings, and the sound is monotonous and uniform, making people feel relaxed, it means that the bearing is good and the motor is running normally. If you hear abnormal noise, you should analyze the cause and deal with it. (2) Hearing obvious rolling and vibration sounds of rolling elements indicates that the bearing clearance is too large or severely worn and needs to be replaced;(3) The sound of the rolling element is dumb and the tone is heavy, which indicates that the lubricating grease of the bearing is too dirty and there are impurities invading. The bearing needs to be cleaned with kerosene and replaced with new lubricating oil. (4) The rolling element has irregular impact sound, it indicates that some rolling elements of the bearing are broken and need to be replaced. (5) The sound of similar whistling, mixed with the rolling sound of rolling elements, indicates that the bearing lacks lubricating grease or the lubricating oil is improperly selected, and it is necessary to add clean lubricating oil or replace suitable lubricating oil.

5. Reasons for abnormal noise

: Host failure. Foreign matter enters the main engine, causing the yin and yang screws to collide with each other and generate howling sound. The clearance between the yin and yang screws and the end face of the bearing is too large; The bearing of the main engine is damaged.

Solution: the host overhaul and the host clearance readjustment. According to industry research data, in general, the screw compressor clearance ratio should be controlled between 0.8 and 1.2 wires. When the screw compressor rotates at high speed, because of the thermal deformation of the tooth profile and the wear of the gear tooth surface, the chasing surface clearance tends to decrease, and the non chasing surface clearance tends to increase. In order to ensure the reliable operation of the compressor for a long time, the clearance between the chasing surface and the non-chasing surface shall be increased and decreased during maintenance, so that the ratio of the clearance between the chasing surface and the non-chasing surface shall be more reasonable between 1.0 and 1.2.

6. Reasons for abnormal noise

: Damaged silencer system. The silencer system of screw compressor is mainly composed of chassis, bracket, frame, door panel, silencer cotton, sealing strip and other parts.

Solution: Check whether the main body of the effect system is in good condition and check whether the connecting bolts are loose. During operation, the compressor will be subjected to loads such as gas force, inertial force, friction force, etc., which will stimulate the vibration of the compressor casing, the chassis of the whole machine, the pipeline system and the support structure. If these vibrations are not restricted by appropriate measures, they will cause abnormal noise.

Summary

compressor abnormal sound in different forms, the reasons are not the same, there are more types of abnormal sound and reasons to be discussed and summarized. However, for a kind of high-speed operation equipment, abnormal noise indicates that the fault has occurred. We must take corresponding measures to investigate and solve the fault as soon as possible to ensure the safe production and operation of the compressor.